Bacillus subtilis-mediated suppression of house dust mite allergic airway inflammation

Abstract

Abstract The incidence of allergic diseases is increasing, with house dust mite allergy, afflicting up to 20% of the population in developed countries. House dust mites (HDM) are a common allergen that can be difficult to avoid and can trigger allergic reactions, including wheezing and shortness of breath. We recently showed that two pretreatments with Bacillus subtilis, a gram-positive bacterium, can prevent murine HDM-induced allergic lung inflammation. We assessed infiltration of eosinophils in bronchial alveolar lavage fluid and found significantly reduced eosinophils following B. subtilis treatment. Our current work addresses the capacity of B. subtilis to provide long-term protection from HDM challenge. Following pretreatment with B. subtilis, we found protection from HDM challenge, determined by quantifying infiltrating eosinophils for two weeks, but lost protection after three weeks. These data suggest a transient protection elicited by B. subtilis and support the need for frequent dosing to maintain suppression of allergic airway inflammation.